Efficient memory allocation scheme for data collection

ABSTRACT

A system and method that provides an integrated circuit which includes a small on-chip buffer to store collected data, thereby shifting the burden of storing the majority of the collected data to external system memory, which is typically comprised of commodity memory chips. Since this external system memory is already in use by other system functions, utilizing such unused regions of this external memory increases overall hardware efficiency, while achieving lower ASIC manufacturing cost.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.09/785,794, filed Feb. 16, 2001 now U.S. Pat. No. 6,836,861, whichclaims the benefit of the filing date of U.S. Provisional PatentApplication No. 60/183,615, filed Feb. 18, 2000. The entire content ineach of the above-cited applications is incorporated herein byreference.

FIELD OF THE INVENTION

The present invention generally relates to the field of data storage.More particularly, the invention relates to an efficient system andmethod for storing and transferring data within a data-collectingsystem, such as statistical information collected from monitoredfunctions in communications transceivers.

BACKGROUND OF THE INVENTION

Orthogonal Frequency Domain Multiplexing (OFDM) transceiverapplication-specific integrated circuits (ASIC), such as those used inwireless modems, often include a data collection function that monitorsvarious components of the circuit and collects corresponding data forsubsequent processing, often by an external processor. Typically, thecollected data is statistical data relating to the performance of therespective components.

The ASIC's data collection function gathers information from internalprocessing units of the ASIC and forwards this information to a hostprocessor for postprocessing. For example, system requirements mayrequire monitoring relevant parameters of internal blocks, such aspower, antenna gain, and the like, with the collected data beingprocessed to determine whether fine tuning of the system is needed.

In order to achieve this data collection function, the prior art systemsemploy large amounts of on-chip memory (e.g., 12K (12,000) bytes) tostore the collected statistical information within the ASIC prior toforwarding that data to the host processor for processing. This approachof using large on-chip memory to store collected statistics isundesirable because it increases the cost of the ASIC, and does notexploit unused regions of existing system memory.

Thus, what is needed is a system and method for efficiently collectingand transferring data from an ASIC or other like circuit to externalsystem memory. The present invention addresses one or more of thesedesirable features.

SUMMARY OF THE INVENTION

Briefly, the present invention is directed to a system and method thatprovides an integrated circuit which includes a small on-chip buffer tostore collected data, thereby shifting the burden of storing themajority of the collected data to external system memory, which istypically comprised of commodity memory chips. Since this externalsystem memory already exists for use by other system functions,utilizing unused regions of this external memory increases overallhardware efficiency, while achieving lower ASIC manufacturing cost.

In one embodiment, the invention is directed to a system for managingdata generated by one or more sources, and includes a host processor andmemory unit, and a circuit including one or more sources, a controllerconnected to the one or more sources, and a buffer memory, where thecontroller is operative to periodically receive data from the one ormore sources, transfer the data to the buffer, and at a predeterminedpoint the buffer is controlled to transfer the data to the memory unit.

In another embodiment, the invention is directed to a method formanaging data in an integrated circuit, including receiving data fromone or more sources within the integrated circuit, storing the data in abuffer memory, transferring the data from the buffer to an externalmemory location upon reaching a predetermined condition, and thenrepeating the process.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will become apparent froma description of the figures, in which:

FIG. 1 shows in block diagram form an overview of one illustrativeembodiment of a system according to the present invention; and

FIG. 2 shows in block diagram form in more detail an overview of anillustrative embodiment of a system according to the present inventionwhich includes, in combination, both a statistics collection functionand diagnostic function.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures, and in particular to FIG. 1, there isshown one illustrative embodiment of a circuit 10 for collecting andtransferring data according to the present invention. Circuit 10receives data from one or more data collecting and/or generating modules12, and forwards such data to a buffer memory device 14. Buffer memorydevice 14 periodically transfers the data to an external system memory16, which is accessed by a host processor 18 for processing of thecollected data, as is described in more detail below.

In one embodiment, circuit 10 is in the form of an application-specificintegrated circuit (ASIC) that is designed to collect data from themodule or modules 12. For example, circuit 10 may interact with aplurality of modules 12, where each module monitors a particular systemfunction and generates corresponding data. Such data can correspond tovarious parameters, such as voltage levels, antenna gain, and the like.Thus, it will be understood by those skilled in the art that the datacan take many different forms. For ease of description, such data willbe collectively referred to herein as “statistics data”. Moreover, whileonly two modules are shown in FIG. 1, it will be apparent that thenumber of modules can be one, two, or any other number of modules.

Circuit 10 includes a controller 20, which in one embodiment is in theform of a statistics output selector (hereinafter referred to as“controller”). As described above, controller 20 may interact with oneor more modules 12. In one embodiment, data capture control signals aretransmitted between the controller 20 and the module(s) 12 over a signalline 22 upon reaching respective time slots. Each module may be assignedto selected time slots, and when those pre-selected time slots aredetected, the controller receives data from that module and writes thereceived data to the buffer 14. Alternatively, the module(s) 12 may bedesigned to perform periodically monitoring and to automatically collectcorresponding data, which is then transmitted to controller 20 over adata bus 24 or any other suitable signal line or lines for writing tobuffer 14. In yet another embodiment, handshaking may be implementedbetween controller 20 and buffer 14 for monitoring the status of thebuffer 14 to determine the progress of the write operation.

In the situation where controller 20 is connected to plural modules 12over data bus 24, controller 20 is preferably designed to perform amultiplexing function to transfer the collected data from plural modulesover one or more data lines 26 to buffer memory device 14. Suchmultiplexing may be conducted in any suitable manner, such as timedivision multiplexing or the like.

Buffer memory device 14 is connected to controller 20 via a pair ofsignal lines 28 and 30. Signal line 28 provides for transmission of thecollected data from controller 20 to buffer memory device 14 fortemporary storage, while signal line 30 provides for the two-waytransmission of write control signals between buffer 14 and controller20, as described above.

Buffer memory device 14 is also connected to an external memoryinterface 32 via signal lines 34 and 36. Signal line 34 provides fortransmission of stored data from buffer memory device 14 to theinterface 32, while signal line 36 provides for the two-way transmissionof read control signals between buffer memory device 14 and interface32.

In one embodiment, when a minimum quantity of new data is present in thebuffer 14, and the external device which will use the data is availablefor processing the data, read controls are asserted to the buffer 14 toretrieve the data from buffer 14 and transfer the data to the externalmemory xx. Thus, when the buffer 14 achieves a predetermined level offullness (based on the size of buffer 14 and the particular statisticsmode), read request signals are transmitted from buffer 14 to interface32. The status of the external device (e.g., processor 18) is thendetermined and, when it is available, the read controls are asserted tobuffer 14, such that the data is transferred to external memory 16 foraccessing by the external device.

Interface 32 connects to external system memory 16 via signal line 38,and transfers the stored data to memory 16 at a predetermined, unusedlocation of that memory 16. Host processor 18, via a processor interface19, may then access memory 16 over signal line 40 and retrieve the datafor processing.

Buffer memory device 14 is a relatively small memory device. In oneembodiment, buffer memory device 14 is capable of storing 128 bytes ofdata. However, it will be understood that the size of buffer memorydevice will vary, depending on the number of modules 12, thecapabilities of host processor 18, and the like. Thus, in one embodimentthe size of the buffer memory can be between about 100 and about a fewkilobytes.

Buffer memory device 14 may also have other attributes, such as an inputpointer (where new data will be written into the buffer), and an outputpointer (where the next item will be read from) and/or a count of thespace used or free. Such attributes may be used during the controlsignal stages of the circuit 10, as is described below.

The operation of circuit 10, in one illustrative embodiment, is nowdescribed in greater detail. Operation begins with controller 20transmitting data capture control signals to the respective modules 12over signal line 22 to coordinate the receipt of data from therespective modules 12. It will be understood that, in the case ofmultiple modules 12, controller 20 may either assign discrete time slotsfor each module 12 to transmit its data, or controller 20 maysimultaneously receive data from multiple modules 12 and perform amultiplexing function to transmit the data to buffer memory device 14.Alternatively, the modules may be programmed to automatically performtheir respective data collection and/or generation functions, and toforward such data on to controller 20.

In any event, prior to transmitting data to buffer memory device 14,controller 20 transmits write control signals to buffer memory device 14over signal line 30. Those control signals may include a request fromcontroller 20 to buffer memory device 14, requesting to transmit data tobuffer memory device 14. Included in the request may be the amount ofdata to be transmitted. Buffer memory device 14 may then determine theamount of available memory and transmit a reply signal to controllerover signal line 30 indicating that it is ready to receive the data.Controller 20 then transmits the data over data line 28, and the data isstored in buffer memory 14.

At a predetermined point in the process, buffer read control signals aretransmitted between buffer memory device 14 and interface 32 overcontrol signal line 36. In one embodiment, interface 32 transmits arequest to read data from buffer memory device 14, and device 14transmits a reply indicating the amount of new data to be read.Alternatively, buffer memory device 14 can transmit a signal tointerface 32 at a predetermined point in the process, for example in thesituation where the buffer memory 14 contains some minimum amount of newdata, or when buffer 14 is full of new data and controller 20 isrequesting to transmit additional data to the buffer 14.

At the appropriate point, for example when the external device (e.g.,host processor 18) is available to access data from external memory 16,buffer memory device 14 then transmits the stored data over data line 34to interface 32, which writes the data to a preselected location inexternal system memory 16, based upon memory control signals transmittedbetween interface 32 and memory 16. Host processor 18 may then accessthe data in memory 16 to process the data.

Referring now to FIG. 2, there is shown an ASIC 40 in which the presentinvention can be implemented. The ASIC includes a plurality of modules,each of which generates data relating to a particular parameter. Inaddition, designated modules may be stimulated during a diagnostics modeof operation with data from input test pins, with such module generatingoutput data that either drives output test pins, or drives anothermodule, which then generates output that drives the test pins. The ASICincludes a Statistics/Diagnostics Bus (SDB) 42 that provides the meansthrough which the normal run-time statistics as well as testing relatedsystem diagnostic information are collected.

Under normal mode of operation, parameters accessible within the ASIC,in groups of up to 128 bytes per burst, may be captured by an SDBController 44 and stored in buffer memory 46 before being relayed to theexternal system, including system memory 47 and a Central ProcessingUnit (CPU) (or Host Processor) 48, for analysis, as described above inconnection with FIG. 1. It will be understood by those skilled in theart that some modules have less than 128 bytes of data per burst to becollected, and that some modules may generate more than 128 bytes perburst.

Within the ASIC 40, datapath modules can generate statistics datacharacterizing system performance and operating conditions on a periodicbasis when the statistics collection function is enabled.

In one embodiment, the respective modules generate data representativeof the respective characteristics being monitored on a per burst of databasis. For example, within one burst, a first one of the modules willgenerate a measurement of the data that it is processing, such askeeping the statistics of the input that it is receiving. Under thecontrol of controller 44, that data is provided to data output selector50 for storage in the buffer memory device 46. Data output selector 50,under appropriate write controls, multiplexes the data from therespective modules onto buffer memory 46. Under buffer read controls, anexternal memory interface 52, such as a Direct Memory Access (DMA)device, provides an interface to external system memory 47, such as aSynchronous Dynamic Random Access Memory (SDRAM). The information storedin external system memory 47 can then be accessed by CPU/Host Processor48, via interface 74 and appropriate software, for use by variousaspects of the system as desired.

In detail, the embodiment of FIG. 2 includes the following datacollecting modules: a Receiver Finite Impulse Response Filter RXFIR 54,Receiver Synchronization block RXSYNC 56, Receiver Front End RXFE 58,Receiver Back End RXBE 60, and Receiver Forward Error Correction blockRXFEC 62, under the control of Receiver Media Access Controllayer/Physical layer RX MAC/PHY 64. Similarly, data (e.g., diagnosticdata) can be collected from Transmit Forward Error Correction blockTXFEC 66, Transmit Digital Signal Processor TXDSP 68, and TransmitFinite Impulse Response filter TXFIR 70. Controller 44 is fed by ClockGenerator CLKGEN 71 which is responsive to clock signals XTAL and MCK.Host processor 48 and external memory 47 communicate with each other andwith controller 44 over an Internal System Bus (ISB)72, via respectiveCPU interface 74, external system memory interface 76, and externalmemory interface 52. Controller 44 can also be involved with handlingdiagnostics under the control of register 78, and provide input/outputclocking and output data and valid signals on output lines 80, 82, and84 for diagnostics purposes.

Thus, it will be understood by those skilled in the art that the presentinvention has utility in various ASICs as well as in other circuits. Thespecific example shown in FIG. 2 is meant for illustrative purposes toillustrate one such implementation.

From the foregoing, it will be apparent that the present inventionefficiently manages the storage of collected data, such as statisticsdata and the like. By shifting the burden of storing the bulk of thecollected data to previously unutilized regions of the external systemmemory, the invention achieves a relatively low-cost ASIC due to therelatively small on-chip memory size, as well as increased hardwareefficiency due to utilization of previously unused region of systemmemory.

While the above description contains many specific features of theinvention, these should not be construed as limitations on the scope ofthe invention, but rather as exemplary embodiments thereof. Many othervariations are possible. Accordingly, the scope of the invention shouldbe determined not by the embodiments illustrated, but by the appendedclaims and their legal equivalents.

1. A system for managing data, comprising: an integrated circuit havinga source of statistics data, a buffer memory, and a controller coupledwith the source, the statistics data relating to one or more parametersof the integrated circuit, the source being assigned a pre-selected timeslot, the controller being operative to receive the statistics data fromthe source when the assigned pre-selected time slot is detected and totransfer the statistics data to the buffer memory; a system memoryexternal to the integrated circuit; and a data processor external to theintegrated circuit and coupled with the integrated circuit via thesystem memory; wherein the buffer memory is instructed to transfer thestatistics data to the system memory upon determining an availability ofthe data processor such that the statistics data can be accessed andretrieved by the data processor from the system memory for processing.2. The system of claim 1, further comprising an external interfacecoupled between the buffer memory of the integrated circuit and thesystem memory external to the integrated circuit, wherein the buffermemory and the external interface are operative to transmit read controlsignals therebetween to coordinate the transfer of the statistics datafrom the buffer memory to the system memory and wherein the interface isoperative to transmit a read control signal upon determining theavailability of the data processor external to the integrated circuit.3. The system of claim 2, wherein the buffer memory is operative totransmit a second read control signal upon the accumulation of apredetermined amount of the statistics data in the buffer memory.
 4. Thesystem of claim 1, wherein the source comprises at least two modules andwherein each of the modules monitors a particular system function andgenerates corresponding statistics data.
 5. The system of claim 1,further comprising a second source of statistics data connected with thecontroller, wherein the second source is assigned a second pre-selectedtime slot and wherein the controller is operative to receive thestatistics data from the second source when the second assignedpre-selected time slot is detected, and to transfer the statistics datafrom the second source to the buffer memory.
 6. The system of claim 1,wherein the controller comprises an output selector that is designed toperform a time division multiplexing operation in the transfer of thestatistics data from the source to the buffer memory.
 7. The system ofclaim 1, wherein the pre-selected time slot assigned to the sourcecomprises a plurality of time slots and wherein the controller isoperative to receive a part of the statistics data from the source whenone of the plurality of time slots is detected.
 8. The system of claim1, wherein the buffer memory of the integrated circuit comprises a firstamount of memory size and the system memory comprises a second amount ofmemory size and wherein the first amount is not greater than the secondamount.
 9. The system of claim 1, wherein the buffer memory and thecontroller are operative to transmit write control signals therebetweento coordinate the writing of the statistics data to the buffer memory.10. The system of claim 1, wherein the one or more parameters compriseat least one selected from a group consisting of voltage level andantenna gain.
 11. The system of claim 1, wherein the statistics datacharacterizes at least one of system performance and operatingconditions.
 12. The system of claim 1, wherein the data processoranalyzes the statistics data after the statistics data has beentransferred to the system memory external to the integrated circuit. 13.The system of claim 1, wherein the integrated circuit further comprisesa second source of diagnostics data relating to a clock line, whereinthe second source is connected with the controller, wherein thecontroller is operative to receive the diagnostics data from the secondsource and to output the diagnostics data from the integrated circuitwithout storing the diagnostics data in the buffer memory of theintegrated circuit.
 14. The system of claim 1, wherein the integratedcircuit is an application-specific integrated circuit (ASIC).
 15. Thesystem of claim 1, wherein the system memory external to the integratedcircuit is an existing memory of the system.
 16. The system of claim 15,wherein the existing memory is designed for use by other functions ofthe system.
 17. The system of claim 16, wherein the controller of theintegrated circuit is operative to utilize unused regions of theexisting memory to store the statistics data from the integratedcircuit.
 18. The ASIC of claim 17, wherein the buffer memory is coupledwith the external memory via an external interface, wherein the buffermemory and the external interface are operative to transmit read controlsignals therebetween to coordinate the transfer of the statistics datafrom the buffer memory to the external memory, and wherein the externalinterface is operative to transmit a read control signal to the buffermemory upon determining the availability of the data processor.
 19. TheASIC of claim 17, further comprising a second source of diagnostics datarelating to a clock line, wherein the controller also receives thediagnostics data from the second source, wherein the controller providesthe statistics data to the buffer memory for storage prior to beingprovided to the external memory, and wherein the controller provides thediagnostics data as an output of the ASIC without storing in the buffermemory.
 20. An application-specific integrated circuit (ASIC) coupledwith an external data processor via an existing external memory, theASIC comprising: a source of statistics data relating to one or moreparameters of the ASIC; a controller for receiving the statistics dataat a pre-selected time slot from the source; a first signal line; asecond signal line; and a buffer memory coupled with the controller viathe first and second signal lines; wherein the controller is operativeto receive the statistics data when the pre-selected time slot isdetected, and to write the statistics data to the buffer memory via thefirst signal line; wherein the buffer memory and the controller areoperative to transmit write control signals therebetween via the secondsignal line to coordinate the writing of the statistics data to thebuffer memory; and wherein the buffer memory is instructed to transferthe statistics data to the external memory upon determining anavailability of the data processor such that the statistics data can beaccessed and retrieved by the data processor from the external memoryfor processing.
 21. The ASIC of claim 20, wherein the first signal linecomprises a one-way transmission line and wherein the second signal linecomprises a two-way transmission line.